Performance Impact with Calculated Columns

[Anonymous]

Hi All,

I am new to PowerBI. Being a Excel user, I know that using lot of Formulas sometimes impacts the performance. Is it the same case with PowerBI? I looks for a similar topic, but could not find any response.

Are my calculated Columns, "calcuated" dynamically? Or stored within Cache as soon as its imported? I have about 1Million+ rows, and use calculated columns to get for example: Month(Date), Create YES/NO flags based of column's values and more.

Should I precalculate these values in my SQL server DB and then import them? Does creating new Calculated values within PowerBU have any mpact on perfromance?

Does using "Custom Column" in Query Editor make any difference? How different is it from Calc column?

Thanks,

Sam

[mike_honey · Accepted solution]

Calculated Columns are not dynamic (unless you are in Direct Query mode) - they are pre-calculated and stored.  Custom Columns from the Query Editor are similar, but the performance is marginally better.  I lean towards them for that reason but mainly because they are much easier to write, debug and test. 

[Anonymous]

Thank you so much for responding!
I am glad that my initial assumption were right about data getting stored! 🙂
I went ahead and created all caclulated queries because the amount of data imported was already huge. People at work started questioning about the performance and thats why I wanted to get it clarified here.

Thank you so much! I will mark your response as Solution. 🙂

"I lean towards them for that reason but mainly because they are much easier to write, debug and test. "

Did you mean Custom columns or Calculated Columns??

[mike_honey]

I meant Custom Columns from the Query Editor.